Facilitated electron transfer by Mn dopants in 1-dimensional CdS nanorods for enhanced photocatalytic hydrogen generation

Abstract

Using sunlight to produce hydrogen gas via photocatalytic water splitting is highly desirable for green energy harvesting and sustainability. In this work, Mn2+ doped 1-dimensional (1D) CdS nanorods (NRs) with...

Interfacial B-Site Ion Diffusion in All-Inorganic Core/Shell Perovskite Nanocrystals

“…The PL spectrum of the CsPbCl 3 core NCs displays a blue emission at 408 nm with a PL QY of 6.1% (blue in Figure a). As the shell grows, a new Mn PL peak rises at 605 nm from the Mn 2+ ions, which is consistent with Mn 4 T 1 → 6 A 1 transition inside the perovskite as well as metal chloride systems. ,− It should be noted that the Mn PL position is sensitive to the crystal field splitting, coordination environment, and dopant location. − Therefore, such a change in PL spectra after CsMnCl 3 shelling could indicate the Mn 2+ diffusion from the CsMnCl 3 shell to the CsPbCl 3 core, resulting in the formation of Mn-doped CsPbCl 3 NCs (i.e., Mn:CsPbCl 3 ). In the Mn-doped core NCs, the host CsPbCl 3 NCs absorb visible light to form excited electrons in the conduction band (CB).…”

“…All-inorganic metal halide perovskites (ABX 3 , X = Cl, Br, or I) have excellent light absorption, tunable band gap, and high charge carrier mobilities, which offer great potential for optoelectronic devices, such as photovoltaics, , electrochemical sensors, , light-emitting diodes (LEDs), , and photocatalysis. , However, the toxicity and instability of lead-based perovskites, such as CsPbX 3 , limit their applications. , To address these issues, lead-free halide perovskite materials have recently attracted attention due to their lower toxicity and higher stability as alternatives to lead-based perovskite nanocrystals (NCs). ,− Some low-toxicity constituents with a perovskite structure include Sn/Ge-based halides, , double perovskites, , and Bi/Sb-based halides. , Mn 2+ ions are also considered potential B-site ions to fabricate perovskite-type materials (e.g., CsMnCl 3 ) for the application of X-ray imaging and LED devices , and can also serve as dopants to significantly tailor the optical properties. ,− Though ideal lead-free candidates could have low toxicity, tunable direct band gaps, high optical absorption coefficients, and compatible stability, the performances of lead-free perovskites are still not yet approaching the spectacular performance of lead-based perovskites (APbX 3 ) . Therefore, finding a method to effectively utilize the merits of lead-based and lead-free perovskite materials is essential for wide applications of perovskites.…”

Nanocrystals of divalent europium-doped CsPbCl3 perovskites: a novel optoelectronic material with dual-emissions

“…S6a, ESI †), similar to the Eu 2+ and Mn 2+ doped case, reported previously. [27][28][29][30][31] The PLQY of the Eu (3 mol%):CsPbCl 3 PeNCs is determined to be 4.2% (Fig. S6b, ESI †).…”

Type-I CdS/ZnS Core/Shell Quantum Dot-Gold Heterostructural Nanocrystals for Enhanced Photocatalytic Hydrogen Generation

“…However, the resulting CdS/ZnS core/shell QDs possess a so-called Type-I band alignment (i.e., the bandgap of the core is embedded in the wider bandgap of the shell), in which both electrons and holes are strongly confined in the semiconductor core region (i.e., CdS core QDs). The low availability of the charge carriers has therefore limited the practical applications of Type-I core/shell QDs in photocatalytic reactions. − In the meantime, semiconductor–metal heterostructural nanocrystals (HNCs) that couple semiconductor NCs with metal NCs have emerged as unique photocatalysts for fuel production with significantly improved efficiency. − Research efforts have been devoted to the delicate synthetic control of HNCs with diverse compositions and morphologies, , which also allow for the study of novel properties generated from the nanoscale semiconductor–metal heterojunction, such as ultrafast charge transfer. − Regardless of the thorough investigations in the morphology control and synergistic effects, the synthesis and utilization of semiconductor–metal HNCs containing Type-I core/shell QDs for photocatalytic reactions have not yet been clearly demonstrated.…”